Article

Detection and Characterization of Wolbachia Infections in Natural Populations of Aphids: Is the Hidden Diversity Fully Unraveled?

University of Poitiers, France
PLoS ONE (Impact Factor: 3.23). 12/2011; 6(12):e28695. DOI: 10.1371/journal.pone.0028695
Source: PubMed

ABSTRACT

Aphids are a serious threat to agriculture, despite being a rather small group of insects. The about 4,000 species worldwide engage in highly interesting and complex relationships with their microbial fauna. One of the key symbionts in arthropods is Wolbachia, an α-Proteobacterium implicated in many important biological processes and believed to be a potential tool for biological control. Aphids were thought not to harbour Wolbachia; however, current data suggest that its presence in aphids has been missed, probably due to the low titre of the infection and/or to the high divergence of the Wolbachia strains of aphids. The goal of the present study is to map the Wolbachia infection status of natural aphids populations, along with the characterization of the detected Wolbachia strains. Out of 425 samples from Spain, Portugal, Greece, Israel and Iran, 37 were found to be infected. Our results, based mainly on 16S rRNA gene sequencing, indicate the presence of two new Wolbachia supergroups prevailing in aphids, along with some strains belonging either to supergroup B or to supergroup A.

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    • "both arthropod and nematode endosymbionts (F) [4]. The strains of Wolbachia detected in Australian spiders [81], were designed as Supergroup G but it was later revealed that it has a wsp gene that is a recombinant between those of A and B supergroups rather than being a distinct new supergroup [8]. "
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    ABSTRACT: Wolbachia are highly extended bacterial endosymbionts that infect arthropods and filarial nematodes and produce contrasting phenotypes on their hosts. Wolbachia taxonomy has been understudied. Currently, Wolbachia strains are classified into phylogenetic supergroups. Here we applied phylogenomic analyses to study Wolbachia evolutionary relationships and examined metrics derived from their genome sequences such as average nucleotide identity (ANI), in silico DNA-DNA hybridization (DDH), G+C content, and synteny to shed light on the taxonomy of these bacteria. Draft genome sequences of strains wDacA and wDacB obtained from the carmine cochineal insect Dactylopius coccus were included. Although all analyses indicated that each Wolbachia supergroup represents a distinct evolutionary lineage, we found that some of the analyzed supergroups showed enough internal heterogeneity to be considered as assemblages of more than one species. Thus, supergroups would represent supraspecific groupings. Consequently, Wolbachia pipientis nomen species would apply only to strains of supergroup B and we propose the designation of 'Candidatus Wolbachia bourtzisii', 'Candidatus Wolbachia onchocercicola', 'Candidatus Wolbachia blaxterii', 'Candidatus Wolbachia brugii', 'Candidatus Wolbachia taylorii', 'Candidatus Wolbachia collembolicola' and 'Candidatus Wolbachia multihospitis' for other supergroups. Copyright © 2015 Elsevier GmbH. All rights reserved.
    Full-text · Article · Jul 2015 · Systematic and Applied Microbiology
    • "Sequence analysis of these genes shows that Wolbachia belongs to a monophyletic clade in the alpha-proteobacterial group (Zhou et al., 1998;Ricci et al., 2002). Wolbachia are classified into 14 supergroups, A-N, based on wsp and 16S rRNA genes (Ros et al., 2009;Augustinos et al., 2011). Supergroups A and B are the most widely distributed in insects (Zhou et al., 1998). "
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    ABSTRACT: Members of the genus Wolbachia are a group of endosymbiotic bacteria that infect a wide range of arthropods and cause reproductive alterations in their hosts. A survey of these endosymbionts in leafhoppers and planthoppers in rice agroecosystems from 20 provinces in 4 different geographic regions of Thailand was carried out during January 2012 to December 2013. Most species were collected from growing rice fields among 5 habitat types surveyed from the Central and the Northeast regions. Infections of Wolbachia were screened by using polymerase chain reaction with wsp, ftsZ, 16S rRNA and groE gene primers and distinguished between A and B supergroup using wsp primers. Species of 15 leafhoppers and 18 planthoppers were collected and identified with 1, 14, 2, 14, 1 and 1 sp. representing the family Aphrophoridae, Cicadellidae, Cixiidae, Delphacidae, Lophopidae and Meenoplidae, respectively. Wolbachia were detected in 1377 of 1849 individuals (74.5%) representing 17 of 33 species (51.5%) of leafhoppers and planthoppers. Wolbachia had not been previously reported from Oliarus sp., Pyrilla perpusilla, Sogatella kolophon and S. vibix. The relative densities of Wolbachia within each individual were determined using quantitative real-time PCR and the result showed that the small brown planthopper Laodelphax striatellus had the highest Wolbachia density. These findings indicated that Wolbachia are distributed throughout leafhoppers and planthoppers from Thailand, suggesting that Wolbachia dynamics in nature may be affected by ecological factors.
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    • "Moreover, Wolbachia sp. from O. nova was not a recombinant between strains of supergroups A, B, C, D, E, F, H and M. The phylogeny based on the concatenated matrix revealed that the roots of the trees were positioned at the base of Wolbachia from the aphid Cinara cerdi. The endosymbiont of Cinara cedri represents supergroup M and its role in the host has not been determined; however, it is speculated that the bacterium may have a nutritional function (Augustinos et al., 2011). The next earliest branching lineages in the trees were Wolbachia sp. from O. nova with a sister group of Wolbachia from all supergroups, with the exception of supergroup M. Bacteria of supergroups A, B, C, D and F and their hosts exhibit obligative mutualism. "
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    ABSTRACT: We determined the distribution of microbial endosymbionts as possible agents of parthenogenesis in Oribatida. We screened mites from 20 species of 14 families suspected to be parthenogenetic from the absence or rarity of males. Our research included parthenogenesis-inducing bacteria Wolbachia spp., Cardinium spp., Rickettsia spp., and additionally Arsenophonus, Spiroplasma and microsporidia that can also manipulate host reproduction. We detected the endosymbionts by PCR-based methods and transmission electron microscopy (TEM) observation of fixed and stained preparations of host cells. We detected Wolbachia only in one Oribatida species, Oppiella nova, by identifying Wolbachia genes using PCR. TEM observations confirmed infection by the endosymbiont in O. nova and its lack in other Oribatida species. Sequence analysis of hcpA and fbpA genes showed that the Wolbachia strain from O. nova was different from strains characterized in some insects, crustaceans (Isopoda), mites (Tetranychidae), springtails (Hexapoda) and roundworms (Nematoda). The analysis strongly suggested that the Wolbachia sp. strain found in O. nova did not belong to supergroups A, B, C, D, E, F, H or M. We found that the sequences of Wolbachia from O. nova were clearly distantly related to sequences from the bacteria of the other supergroups. This observation makes O. nova a unique Wolbachia host in terms of the distinction of the strain. The role of these micro-organisms in O. nova remains unknown and is an issue to investigate.
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